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Electronics Calorimeter trigger Not all the calorimeter channels are read for each event Following HRS trigger, stop ARS. 30MHz trigger FADC digitizes all calorimeter signals in 85ns window. - Compute all sums of 4 adjacent blocks. - Look for at least 1 sum over threshold - Validate or reject HRS trigger within 340 ns Not all the Proton Array channels are read for each event.

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Analysis status - What is done Left HRS efficiency (detectors, tracking …) determined All good runs selected and total integrated luminosity extracted Calorimeter calibration done for almost all data Proton Array calibration done for a part of the data and still in progress Parameters of the wave form analysis and the clustering optimized Coincidence time of all detectors precisely adjusted All geometrical offsets taken into account

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Analysis status – preliminary Sigma = 0.6ns 2 ns beam structure Time difference between the electron arm and the detected photon Selection of events in the coincidence peak Determination of the missing particle (assuming DVCS kinematics) Check the presence of the missing particle in the predicted block (or region) of the Proton Array Sigma = 0.9ns Time spectrum in the predicted block (LH 2 target)

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Conclusion -Requires wave form electronics - 10% of detector components almost unusable as expected after 3 months of data taking We have demonstrated that in Hall A with High Resolution spectrometer and a good calorimeter, we are able to measure: Real and Imaginary parts of DVCSBH interference: Work at precisely defined kinematics: Q 2, s and x Bj Absolute cross sections and cross section difference are determined with the precision of HRS (better than 5%) Analysis is in progress But Work at a luminosity up to Deep π 0 electroproduction cross-section almost finalized